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How is a rectangular bellows made?

Sep. 19, 2019

The rectangular corrugated compensator is manufactured by welding of pipes. The smaller one can be welded by one pipe, and the large size can be welded by two or three pipes. The main function of the rectangular corrugated compensator is to compensate for the displacement caused by the thermal expansion and contraction of the pipe. Rectangular corrugated compensators are often used to compensate pipelines through structural expansion joints, seismic joints and settlement joints.

Since the corrugated compensator works with the highest force on the top, the top is welded with a tube and the weld is not allowed. The welding manufacturing process mainly includes cold bending and hot bending. Below, Henan Shunying New Energy Co., Ltd. will introduce you briefly.

First, cold bending manufacturing

The cold bend of the corrugated compensator steel tube can be manufactured on a production platform using a manual bender and bent at a normal temperature. The membrane parameters of the pipe bender must conform to the outer diameter of the steel pipe and the bending radius. When manufacturing with a pipe bender, the angle should be 3°-5° more than the specified one.

Second, hot bending manufacturing

The bending of the steel pipe under heating is called hot bending, and the hot bending is divided into a non-pleated sanding pipe and a wrinkled and unfilled pipe. Rectangular corrugated compensators typically use a wrinkle-free sanding bend. The main process includes the steps of scribing, sand filling, heating, bending, cooling and heat treatment. Each process is critical to the quality of the bend and should be carried out in accordance with the process specifications. After the rectangular corrugated compensator is manufactured, its centerline size should meet the size requirements listed in the standard series. There shall be no defects such as cracks, metal delamination and over-burning on the surface of the pipe at the bend. The rectangular corrugated compensator should adopt the cold drawing method for pre-stretching, and the pre-stretching adopts the jack and the puller tool.